Method of vulcanizing rubber treads to decks



R. E. MORRIS METHOD OF VULCAKIZING .RUBBER TREADS T0 DECKS Filed Aug. 18, 1942 i A m m.

Jan. 2, 1945.

PYRAMID 'TREAD FABRIC INSERT UNVULCANiZED LAYER CEMENT p aK INVENTOR BY Rus {fiLMuRygZ 7 Tom Patented Jan. 2,1945 UNITED STATES'PATENT OFFICE;

METHOD or VULCANIZING RUBBER TREADS T nncxs i Ross E. Morris, Vallejo, cam.

Application August 18, 1942, Serial No. 455,239 Claims. (cl. 154-2) (Granted under the act of March 1883, as amended April 30, 1928; 370 0. G. 757) This invention relates to deck treads and t layers of tread are cut away to show underlying the new and improved method of applyin the l and Y r I said treads to the surface of a metal deck. More Fig; 2. is a elevatiohal side e particularly, this invention relates to improves Shown on the drawing, he reference 1111- ments in the method of securing deck treads set 5 meral It! indicates the metal deck to which is apforth in my copending application, Serial No. p ed a cement coating e tread is Shown 396,335, filed June 2, 1941. as composed of an upper and lower layer l4 and Heretofore, fully vulcanized mattings or t [2 respectively; having an intermediate lighthave been secured to the surfaces on the metallic weight fab i e W ch s Preferably P decks of ships in order to obtain an anti-slip 10 pared from a square wovenfabric weighing not tread. Considerable difi'iculty has been expeflmore than 2.6 ounces per square yard. The upper enced in the past in maintaining good adherence layer is o of vulcanized stock of natural between the mattings an be k f This or synthetic rubber having a suitable anti-slip difficulty was traceable to failure in some design impressed upon its top surface. The lower stances between the cement and the metal and layer 12 is composed of all llnvllleallized 01-1111- in othe rinstances to failure between the cement cured stock of natural or synthetic rubber. The and the matting. With the advent of rubbermethod of manufacture 0f theSeneW d i halide, rubber-hydrohalide, and thermoprene ceproved t s will be more pa i ula ly s t forth ments, the difiiculties, encountered in Obtaining Y later in this specification. proper adherence between the cement and the he method of securing the composite treads to metal were apparently overcome. However, the deck Surface follOWS! these cements were found to produc an insecure Process with neoprene-The following steps bond between the fully vulcanized mattings and a applicable Where the deck covering matethe cement. I have discovered that a superior rial. s a polymerization P 91 l and highly satisfactory bond may be obtained bedime-1,3, w i h is m ally known as nee; tween the cement and the matting or tread by prone, as one of its constituents. using a composite matting having an u l Preparation of the decks-In order that satisized lower layer and a vulcanized upper layer factory adhesion between the tread and the deck upon which an anti-slip design is impressed, said may be obtained, it is absolutely necessary and essential that the metal surface of. the deck be agreat resistance towear and abrasion. In this perfectly cleanbe o application of the cement. manner I have designed a deck tread which utin unpainted deck may be cleaned by scrubbing lizes the best abrasive-resisting top stock availit with a strong hot aqueous solution of tri-- able. and the best bottom stock to adhere to the sodium ph spha e (D t or s i m biearbon' bonding cement. ate, thoroughly washing with fresh water, dryin 1 Unvulcanized natural rubber compositions and and then grit blasting with a grit free from oil unvulcanized or uncured synthetic compositions ,orgrease: Apainted d k ul Cleaned by possess an adhesive q ality not found in the same chipping the paint fro he c Su washcompositions after they have been fully vulcaning the chipped areas with a suitable paint sol:- ized. I propose, therefore, to utilize this superior 40 vent, wire brushing and then'grit blasting with adhesive quality of the unvulcanized material and a clean grit. In view of the fact that grit blast: synthetic rubber compounds to obtain a superior. ing is unfavorable on board ship because of the bond between he matting or tread and the possibility of and dangers resulting from the grit cement. finding entrance into rotary machines, the deck i It is an object of this invention, therefore, to may be cleaned by being buffed-with a power provide a new and. improved composite deck driven fi l l a grit mi t eloXite tread. paper. I have noted 'in practical applications of It is a further object of this-invention to prothis invention that a power driven wire'brush vide a new and improved method of securing such when used for final cleaning leaves a thin film of deck treads to a metallic surface. r grease 0r dirt on the metal surface; consequently,

It is also a further object of this invention to its use is not recommended except for shallow provide a method of seeming a composite deck crevices that cannot be cleaned otherwise. In. tread having a lower stock of unvulcanized ruball events, the deck surface. should be bright, her in which an ultra-accelerator is introduced rough and free o a s'o rust, grease into the lower stock by difiusion so that the botdirt.

tom layer can be made to vulcanize in several The location of the treadsis preferably marked days at ordinary temperatures. out on the clean decksurfaces by using a mask On the drawing: of scotch tape. The size of the marked-out Fig. 1 is a plan view of the composite product areas should be /2" or so larger in both dimenwhich embodies this invention in which the upper to sions than the size of the tread, care being exer- 2 ascaeoe cised to see that no lapped joints or crevices for vulcanizing the top layer. The mold is condeeper than are contained within the masked structed in such a manner as to give a pyramid area. All rivets included within the area masked impression on the top surface of the upper layer out should have their heads ground flush with of the tread. The top platen of the press is water the deck surface. 5 cooled so as to prevent transmission of heat to Application of cements-The cement is prefthe unvulcanized bottom layer of the tread. The erably applied to a cold deck which has been bottom surface of the tread is protected by the protected from the direct rays of the sun and holland cloth during vulcanization of the top should also be applied only in dry weather with layer in the press so that the bottom surface will an outside temperature not lower than 55 remain perfectly clean and in an unvulcanized Fahrenheit. Before applying the cement, the or uncured state, thus presenting an unvulcandeck is washed and scrubbed with carbon tetraized surface for the cement to adhere to when chloride or a clean rag wet with toluene or other it is attached to the deck. aliphatic or aromatic solvent to remove all traces Ithas been observed that the cloth impression of oil or grease. The portion of the deck to be faces of commercial mattings are all contamicovered is then painted with a single thin coat nated with the soap-stone, mica, or other suitable of rubber chloride or other rubber halidecement, lubricating agents. These lubricating agents are which cement has been thoroughly stirred before used to prevent the matting from sticking to the being applied to the deck. It is important to canvas during the vulcanization in the press. note that only one thin coat of this cement is These lubricating agents also effectively prevent required; a heavy coat or more than one coat the matting from adhering to the bonding agents will impair the adhesive quality of the tread. when securing the matting to the deck surface After the cement has dried for one hour, a coat and are therefore detrimental to the adhesion of of a cement prepared by dissolving a stock the matting and should not be used. of the unvulcanized lower layer of the deck tread 25 When using a hard rubber mold in the hyin toluene or other suitable solvents is applied to draulic press having an overall thickness of 3%"? the area coated with the rubber halide cement. a. curing time of 45 minutes with 60 lb. p. s. i. This neoprene cement is preferably brushed on steam pressure in the lower platen of the hyto obtain an even application and must be allowed draulic press has proven to produce satisfactory to dry for one hour. A second coat of the prevulcanization and anti-slip tread impressions on pared neoprene cement is likewise applied and the upper layer of tread, with the backing stock permitted tordry for one hour. A third coat is showing no sign of vulcanization. The bottom applied and allowed to dry for exactly ten minlayer may be tested to see that it has not vulutes. It is important that a single coat of rubcanized by trimming back the outer edge of the her chloride or rubberchalide cement and at least lower tread for a distance of 1%". For best reone coat of neoprene be applied immediately sults, the treads manufactured in accordance after the deck has been cleaned and the area with the process referred to above should be inover which the treads are to be placed has been stalled on the deck within seven daysafter vulmarked out. y canization and during the time interval between Preparation of the covering materials-In man- 40 vulcanization and actual application to the deck, ufacture of the composite treads, a coating of the prepared treads should be stored in a space cement dough made from the stock of the upper maintained at a temperature with the range of vulcanized layer of the tread is spread on both 85 to 100 Fahrenheit.

\ sides of the fabric insert IS. A stock of the Laying the c0vering.While the last coat of following composition has proven satisfactory for neoprene is drying for the ten minute period, the the upper vulcanized layer: 'holland backing cloth is stripped off the back or ggggg fg mg-g 235E312 ii iigfiiofiliy iiifibifig fifih i ififiii 533333fggg gg;ggg g;ggggflggg;g fiigt tiififiriici ififiiiiiiiiifiift.I??? on) Y 20.0 tacky after this treatment with toluene. After the we a mstars. assassinate.2322.12.22: Pelletex (semi-ereinforcing carbon black) 75.0 gg i' s gggg g g g i I; 22

' gzzgz f ggggg' salt of 1 o In applying the tread, every effort should be made zinc n-fidn I, to prevent the trapping of air. between the tread and the cemented surface. This can best be done The coated fabric insert is applied to the back by first pressing one end of the tread into posistock while the latter is still warm. A satistion on the deck hile holding up the other end factory formula for the backing stock is given of the tread. A heavy iron roller, not more than below: 4" wide and weighing at least 50 lbs. per inch of contact is .then rolled over at the lower end and Neoprene typeGN "100.0 Y back and forth over the tread working toward, #3 (171 (10%) m 1137' the otherend until..-the entire tread has been dr carbon solventln- "a- 3.0 mned down I V r r gag "a""" 1 j Tr mming the c0vr.'-After the [treads have 1"" 7 been down for about twenty-four hours the-cor- This particular composition is calendered onto a" "nersrare rounded at about a 2." radius and the holland cloth backing so as to have a fln1shed'70 edges are beveled. *Itis'important-thatthe bevel gauge of 0.060 .inch and tha topstock is -calenbe made at a relative flat angle. 5 I dered on to the fabric insert so as to have a fln- The aboveprocess is specifically limited to the ished gauge of 0.070 inch. The assembled tread application of coats of neoprene cement. with the top surface down is then placed in a This is, however, a minimuni. requirement and. mold and the mold inserted into ahydrauiic press in casethe deck is severely pitted, more than three I cam'zed layer can be cemented of rubber halide cement and surface of the tread may be Union Solvent #8" instead of -"ber.When, natural rubber is used as a deck covering rather than a material containing neoprene, ,the process may be modified as follows:

l. A rubber hydrohalide or thermoprene cement may be used instead of the rubber halide cement specified above. If thermoprene cement is used, such as that obtainable on the market under the trade name of Vulcalock, and containing a cyclicized rubber dissolved in an aromatic solvent, one coat of a 50-50 mixture of thermoprene cement and a solvent such as toluene is applied to the deck surface immediately after the sand blasting operation. This is then followed by three coats of a 100% thermoprene cement. Each coat prior to the application i except the last is'allowed .to dry until it is no longer tacky.

Typical formulas for the top and bottom stock which are used when the composite tread is made of a natural rubber composition are given below: Top stock Smoked sheet (natural rubber) 100.0 Pelletex black (semi-reinforcing) 75.0 Zinc oxide v 5.0 Heliozone (sunproof wax) 1.0 Stearic ac 3.0 Neozone A (phenyl-alpha-naphthylamine) 1.0 R. P, A. #2 33 A; naphthyl-beta-mercaptan, 66 inerthydrocarbon) 0.5 Captax (memaptobenzothiazole) 1.0 Zimate (zinc dimethyl dithiocarbamate) 0.1 Sulfur 2.5

Bottom stock (not to be cured) Smoked sheet 100.0 Brown factice (vulcanized oil) 25.0 Mineral oil 10.0 Neozone A V 2.0 R. P. A. #2 1.0

The pr mary advantage in the use of rubber is that an ultra accelerator can be introduced into the unvulcanized bottom layer by diffusion. As yet, no method has been presented for introducing an ultra-accelerator by diffusion into a neoprene,

' tures is improved by The term thermoprene cement is intended to inthe tread by using sand bags and at a pressure of approximately 25 lbs. per square foot. These bags are allowed to remain in place for atleast twenty-four hours and then they may be removed and the edges of the tread may be beveled and the comers rounded.

Instead of using sand bags, a heavy corn roller, not more than 4" wide and weighing at least lb. per inch of contact may be rolled over the lower end and back and forth over the tread working toward the other end until the entire tread has been rolled down.

The following is a typical formula for the bottom stock adopted to be cured by diffusion of carbon disulfide:

od outlined above using a thermoprene cement- .Vulcalock and after storage for eight months; the adhesion of the tread to the steel was tested and found to be 37 lb. per inch width at 80 F. and 4 lb. per inch width of tread at 150 F. At 80 the test strips tore within the rubber thereby showing the rubber-Vulcalock bond to be stronger than the rubber itself. At 150 F., the test strip tore loose at the Vulcalock to metal bond. Since the rubber hydrohalide' cements are less thermo plastic than is Vulcalock or other thermoprene cements, the adhesion at high temperausing a hydrohalide cement.

clude as a class the various cyclo-rubbers as defined in the U. S. Patents Nos. 1,605,180; 1,617,- 588; 1,744,880; and the publications by The Research Association of British Rubber Manufacturers, 1935, page 28, Rubber, Physical and Chemical Properties, by T. R. Dawson and B. D. Porritt, and also as set forth in the "Journal of Industrial and Engineering Chemistry, volume 19, page 1325, 1927.

butyl rubber, or but-adiene copolymer rubbers.

By. using accelerator diffusion, the bottom unvulunvulcanized state and attain a state of vulcanization in several days at ordinary temperatures.

To introduce an ultra-acceleration ,by diffusion,

to the deck in itsit is preferable to weigh down area of the decks' rubber halide The invention described herein may be manufactured and used by or for the Government of the-United States of America for governmental purposes without the payment of any royalties thereon or therefor.

I claim: v

1. A composite matting adapted to be cemented to a metal deck to form an anti-slip treadtherefor comprising an upper layer of vulcanized rubher-like polymerized chloroprene having an antislip design impressed upon its-exposed surface, a lower layer of plastic unvmcanizedrubber-like polymerized chloroprene,- and an intermediate layer of a fabric. f V

2. A'product comprising the composite matting deflned in claim 1 and including a layer of metal, and a layer of a cement containing a interposed between the layer of metal and the layer of plastic unvulcanized rubchloroprene of said matting.

3. The method of tread defined in claim 1 to a metal deck surface which includes the steps "of; washing -a, cleaned surface with a rubber solvent, coating said washedarea with a thin layer of rubber halide cement. applying to the rubber halide cement,

securing the composite deck after it has dried, at least three coats of a 25% cement prepared by dissolving the stock of said unvulcanized layer in a solvent, each coating of said 25% cement being applied only after the previously applied coating has dried completely, superimposing said tread upon said cemented area with said lower layer adjacent thereto before the last coating of said 25% cement has dried completely so that said .unvulcanized lower layer will form a firm bond with said cement.

4. The method of securing a composite deck tread comprising an upper layer of vulcanized polymerized chloroprene having an anti-slip tread impressed thereon upon its exposed surface and a lower layer of uncured plastic polymerized chloroprene to a metal deck surface which includes the steps of coating a cleaned area of the decks surface with a thin layer of a rubber halide cement, applying to said cement-coated area after it has dried a coating of a cement prepared by dissolving a stock of uncured polymerized chloroprene in a solvent, and placing said composite tread on said cement-coated area with its uncured surface downward before said polymerized chloroprene cement has completely dried whereby to form a secure matting-and said cement. V v

5. The method of securing a deck tread comprising an upper layer of vulcanized polymerized chloroprene having an anti-slip tread"impressed thereon upon its exposed surface anda lower layer of uncured plastic polymerized chloroprene to ametal deck surface which includes the steps 7 of coating a clean area of the decks surface with a thin layer of rubber hydrohalide cement, ap-

. plying to said cement-coated area, after it has dried, a coating of a cement prepared by dissolving a stock of uncured polymerizedchloroprene in a solvent, scrubbing the exposed surface of the unvulcanized layer of said tread with 'an aromatic solvent, and placing said composite tread onsaid cement-coated area with the scrubbed surface downward before said polymerized chloroprene cement has completely dried whereby to form a secure bond between said matting and said cement.-

ROSS E. MORRIS.

bondbetween the said' 

